dt: introduce for_each_available_child_of_node, of_get_next_available_child

Macro for_each_child_of_node() makes it easy to iterate over all of the
children for a given device tree node, including those nodes that are
marked as unavailable (i.e. status = "disabled").

Introduce for_each_available_child_of_node(), which is like
for_each_child_of_node(), but it automatically skips unavailable nodes.
This also requires the introduction of helper function
of_get_next_available_child(), which returns the next available child
node.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/of/base.c b/drivers/of/base.c
index c181b94abc363b64a4a38c2e39625b7564dc2267..d4a1c9a043e12d3572faefe9a9fd11a1683cdd97 100644 (file)
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -363,6 +363,33 @@ struct device_node *of_get_next_child(const struct device_node *node,
 }
 EXPORT_SYMBOL(of_get_next_child);
 
+/**
+ *     of_get_next_available_child - Find the next available child node
+ *     @node:  parent node
+ *     @prev:  previous child of the parent node, or NULL to get first
+ *
+ *      This function is like of_get_next_child(), except that it
+ *      automatically skips any disabled nodes (i.e. status = "disabled").
+ */
+struct device_node *of_get_next_available_child(const struct device_node *node,
+       struct device_node *prev)
+{
+       struct device_node *next;
+
+       read_lock(&devtree_lock);
+       next = prev ? prev->sibling : node->child;
+       for (; next; next = next->sibling) {
+               if (!of_device_is_available(next))
+                       continue;
+               if (of_node_get(next))
+                       break;
+       }
+       of_node_put(prev);
+       read_unlock(&devtree_lock);
+       return next;
+}
+EXPORT_SYMBOL(of_get_next_available_child);
+
 /**
  *     of_find_node_by_path - Find a node matching a full OF path
  *     @path:  The full path to match

diff --git a/include/linux/of.h b/include/linux/of.h
index 5919ee33f2b7b2d930fa3f6dd877984be5ed5e0d..1b1163225f3b8ab1eafacbb21e83ab8f86d50d42 100644 (file)
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -190,10 +190,17 @@ extern struct device_node *of_get_parent(const struct device_node *node);
 extern struct device_node *of_get_next_parent(struct device_node *node);
 extern struct device_node *of_get_next_child(const struct device_node *node,
                                             struct device_node *prev);
+extern struct device_node *of_get_next_available_child(
+       const struct device_node *node, struct device_node *prev);
+
 #define for_each_child_of_node(parent, child) \
        for (child = of_get_next_child(parent, NULL); child != NULL; \
             child = of_get_next_child(parent, child))
 
+#define for_each_available_child_of_node(parent, child) \
+       for (child = of_get_next_available_child(parent, NULL); child != NULL; \
+            child = of_get_next_available_child(parent, child))
+
 static inline int of_get_child_count(const struct device_node *np)
 {
        struct device_node *child;